1. Field of the Invention
The present invention relates generally to a drum type washing machine, and more particularly to a drum type washing machine including a balancer capable of rapidly reducing vibration of a spin tub.
2. Description of the Related Art
In general, a drum type washing machine rotates a drum so that the laundry loaded in the drum moves upward and then drops from the top to the bottom of the drum, thereby washing the laundry. The drum type washing machine includes a housing forming an external appearance of the drum type washing machine, a water reservoir accommodated in the housing to receive water therein, a spin tub rotatably installed in the water reservoir, and a driving motor generating rotational force by receiving electric power so as to rotate the spin tub connected to a rotating shaft of the driving motor.
In addition, the drum type washing machine is provided with a shaft flange formed at the center thereof with a rotating shaft and fixed to a rear surface of the spin tub so as to uniformly transfer the rotational force of the driving motor to the rotating shaft, and a balancer fixed to the rear surface of the spin tub so as to rapidly reduce vibration generated when the spin tub is rotated.
The shaft flange includes a hub section for installing the rotating shaft, and a plurality of arm sections extending radially outward from the hub section so as to be fixed to the rotating shaft. The balancer includes a balancer housing formed with an annular race that allows a mass accommodated in the balancer housing to move in the circumferential direction, and a ball movably installed in the annular race so as to serve as the mass. The balancer housing includes first and second balancer housings coupled to each other through fusion welding while forming the race therebetween.
However, according to the balancer having the above structure, the ball accommodated in the balancer housing is subject to centrifugal force during the rotation of spin tub, so the ball repeatedly collides with the first and second balancer housings. If the ball applies such impact to the first and second balancer housings for a long period of time, the connection part between the first and second balancer housings is weakened, so that the first balancer housing is separated from the second housing. In this case, the ball accommodated in the race of the balancer housing may move out of the race.